Multi-piece intervertebral implants

ABSTRACT

Intervertebral implants for implanting into an intervertebral space are provided. The implants can comprise one or more layers that are operably attached to one another. An implant can comprise a first layer having a first mating surface that mates with a second mating surface of a second layer. The first mating surface and the second mating surface can have features that allow them to complement each other. The implants can include one or more bore holes for receiving a fixation member. The bore holes can be horizontal, vertical or diagonal. In some cases, the bore holes will be blind bore holes.

CROSS REFERENCE TO RELATED APPLICATIONS

This patent application is a continuation of U.S. patent applicationSer. No. 15/368,771, filed Dec. 5, 2016, which is a continuationapplication of U.S. patent application Ser. No. 14/956,427, filed Dec.2, 2015, now issued as U.S. Pat. No. 9,539,102, which is acontinuation-in-part application of U.S. patent application Ser. No.14/085,318, filed Nov. 20, 2013, now issued as U.S. Pat. No. 9,398,960,which is a continuation-in-part application of U.S. patent applicationSer. No. 13/785,856, filed Mar. 5, 2013, now issued as U.S. Pat. No.9,204,975, which is a continuation-in-part of U.S. patent applicationSer. No. 13/559,917, filed Jul. 27, 2012, now issued as U.S. Pat. No.8,961,606, which is a continuation-in-part of Ser. No. 13/267,119, filedOct. 6, 2011, which claims priority to U.S. Provisional Application61/535,726, filed on Sep. 16, 2011, the entire contents of which areincorporated by reference herein in their entities for all purposes.

FIELD OF THE INVENTION

The present invention is generally directed to intervertebral implantsand in particular, spacers for introducing into an intervertebral space.

BACKGROUND OF THE INVENTION

Spinal fusion procedures are performed to alleviate pain caused bytrauma, disc herniation or spondylosis. In some procedures, portions ofa spinal disc can be removed and replaced by an intervertebral implantdesigned to assist in the fusion process. There thus is a need forimproved intervertebral implants that can be inserted into anintervertebral space between two vertebrae.

SUMMARY OF THE INVENTION

Various embodiments of intervertebral implants are provided. In someembodiments, an intervertebral implant comprises a first layer having asuperior surface for contacting a vertebral body and a second layerhaving an inferior surface for contacting a vertebral body. The secondlayer is operably attached to the first layer. The implant furthercomprises a bore hole that extends through at least a portion of thefirst layer and the second layer, wherein the bore hole has a firstopening that opens at one of either the superior surface of the firstlayer or the inferior surface of the second layer and a second openingthat is blocked by one of either the first layer or the second layer.

In other embodiments, an intervertebral implant comprises a first layerhaving a superior surface for contacting a vertebral body and a secondlayer having an inferior surface for contacting a vertebral body. Thesecond layer is operably attached to the first layer to form asingle-bodied implant. The implant further comprises a bore hole thatextends through at least a portion of the first layer and the secondlayer, wherein the bore hole has a first opening that opens at one ofeither the superior surface of the first layer or the inferior surfaceof the second layer and a second opening that opens at a sidewall of thesingle-bodied implant formed by the first layer and the second layer.

In other embodiments, an intervertebral implant comprises a first layerhaving a first upper surface for contacting a vertebral body and a firstlower surface opposite the first upper surface. The first lower surfaceincludes one or more stepped features. The implant further comprises asecond layer having a second lower surface for contacting a vertebralbody and a second lower surface opposite the second upper surface. Thesecond upper surface includes one or more stepped features thatcomplement the first lower surface of the first layer when the firstlayer and second layer are pressed together. In addition, the implantcomprises a bore hole that extends through at least a portion of thefirst layer and the second layer.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be more readily understood with reference to theembodiments thereof illustrated in the attached figures, in which:

FIG. 1 is a front perspective view of a multi-layered implant havingflat faces and vertical bore holes formed therein according to someembodiments.

FIG. 2 is front perspective view of a multi-layered implant having flatfaces and diagonal bore holes formed therein according to someembodiments.

FIG. 3 is a top perspective view of a layer of a multi-layered implanthaving a face with a waffle pattern according to some embodiments.

FIG. 4 is a top perspective view of a complementary layer to the layerin FIG. 3 according to some embodiments.

FIG. 5 is a cross-sectional view of a multi-layered implant havinglayers with mated waffle faces according to some embodiments.

FIG. 6 is a top perspective view of a layer of a multi-layered implanthaving block features according to some embodiments.

FIG. 7 is a top perspective view of a complementary layer to the layerin FIG. 6 according to some embodiments.

FIG. 8 is a cross-sectional view of a multi-layered implant having blockfeatures and diagonal bore holes formed therein according to someembodiments.

FIGS. 9A and 9B illustrate different views of a multi-layered implanthaving layers with interlocking curved faces according to someembodiments.

FIGS. 10A-10C illustrate different views of a multi-layered implanthaving a mating interface comprising waffle-pattern features accordingto some embodiments.

FIGS. 11A-11C illustrate different views of a multi-layered implanthaving a mating interface comprising geometrical inserts according tosome embodiments.

FIGS. 12A-12C illustrate different views of a multi-layered implantincluding horizontal bore holes according to some embodiments.

FIGS. 13A-13C illustrate different views of a multi-layered implantincluding diagonal bore holes according to some embodiments.

FIG. 14 is a top perspective view of a layer of a multi-layered implanthaving receiving windows according to some embodiments.

FIG. 15 is top perspective view of a complementary layer to the layer inFIG. 14.

FIG. 16 illustrates different views of a multi-layered implant includinga layer with a mating face including angled protrusions according tosome embodiments.

FIG. 17 is a top perspective view of a layer of a multi-layered implantcomprising block features according to some embodiments.

FIG. 18 is a top perspective view of a complementary layer to the layerin FIG. 17.

FIG. 19 is a cross-sectional view of a multi-layered implant havingdiagonal bore holes formed therein.

FIGS. 20A-20D illustrate different views of an implant having teethaccording to some embodiments.

FIGS. 21A-21D illustrate different views of an alternative implanthaving teeth according to some embodiments.

FIGS. 22A-22D illustrate different views of an alternative implanthaving teeth according to some embodiments.

FIGS. 23A-23E illustrate different views of an alternative implanthaving teeth according to some embodiments.

FIGS. 24A-24E illustrate different views of an alternative implanthaving teeth according to some embodiments.

FIGS. 25A-25E illustrate different views of an alternative implanthaving teeth according to some embodiments.

FIGS. 26A-26D illustrate different views of an implant having ridgesaccording to some embodiments.

FIGS. 27A-27E illustrate different views of an alternative implanthaving ridges according to some embodiments.

FIGS. 28A-28E illustrate different views of an alternative implanthaving ridges according to some embodiments.

FIGS. 29A-29E illustrate different views of an alternative implanthaving ridges according to some embodiments.

FIGS. 30A-30F illustrate different views of an alternative implanthaving ridges according to some embodiments.

FIGS. 31A-31F illustrate different views of an alternative implanthaving ridges according to some embodiments.

FIGS. 32A-32G illustrate different views of a multi-layered implanthaving various mating features according to some embodiments.

FIGS. 33A-33G illustrate different views of an alternative multi-layeredimplant having various mating features according to some embodiments.

FIGS. 34A-34G illustrate different views of an alternative multi-layeredimplant having various mating features according to some embodiments.

FIGS. 35A-35G illustrate different views of an alternative multi-layeredimplant having various mating features according to some embodiments.

FIGS. 36A-36F illustrate different views of an alternative multi-layeredimplant having various mating features according to some embodiments.

FIGS. 37A-37G illustrate different views of an alternative multi-layeredimplant having various mating features according to some embodiments.

FIGS. 38A-38C illustrate some embodiments of a multi-piece implanthaving a pair of bore holes.

FIGS. 39A-39C illustrate some embodiments of an alternative multi-pieceimplant having a pair of bore holes.

FIGS. 40A-40C illustrate some embodiments of an alternative multi-pieceimplant having a pair of bore holes.

FIGS. 41A-41C illustrate some embodiments of an alternative multi-pieceimplant having a pair of bore holes.

FIGS. 42A-42C illustrate some embodiments of an alternative multi-pieceimplant having a pair of bore holes.

FIGS. 43A-43C illustrate some embodiments of an alternative multi-pieceimplant having a pair of bore holes.

FIGS. 44A-44C illustrate some embodiments of multi-piece implant havingan inner concentric member.

FIG. 45 is a cross-sectional view of a multi-piece implant having a pairof bore holes according to some embodiments.

FIG. 46 illustrates a multi-piece implant having concentric componentsaccording to some embodiments.

FIG. 47 illustrates a multi-piece implant having an insertable componentaccording to some embodiments.

FIG. 48 illustrates an alternative multi-piece implant having aninsertable component according to some embodiments.

FIGS. 49A and 49B illustrate different embodiments of a multi-pieceimplant having components with engaging surfaces.

FIG. 50 illustrates a multi-piece implant having a connecting platemember according to some embodiments.

FIG. 51 illustrates a multi-piece implant having threaded componentsaccording to some embodiments.

FIGS. 52A and 52B illustrate a multi-piece implant having a concentricinner member according to some embodiments.

FIG. 53 illustrates an insertable member of a multi-piece implantaccording to some embodiments.

FIGS. 54A-54C illustrate an implant having shims according to someembodiments.

FIGS. 55A and 55B illustrate an alternative implant having shimsaccording to some embodiments.

FIGS. 56A-56C illustrate an alternative implant having shims accordingto some embodiments.

FIG. 57 illustrates a shim according to some embodiments.

FIGS. 58A-58D illustrate an alternative implant for receiving a plugaccording to some embodiments.

FIGS. 59A-59C illustrate an alternative implant assembled from two ormore members in series according to some embodiments.

FIGS. 60A-60D illustrate an alternative implant assembled from two ormore members in series according to some embodiments.

FIG. 61 illustrates an alternative implant assembled from two or moremembers in series and in a stacked configuration according to someembodiments.

FIGS. 62A and 62B illustrate different views of an alternative implantwith a FIG. 8 pin according to some embodiments.

FIG. 63 illustrates an unassembled implant with a FIG. 8 pin accordingto some embodiments.

FIGS. 64A and 64B illustrate different views of an assembled implantwith a FIG. 8 pin according to some embodiments.

FIGS. 65A and 65B illustrate different views of a FIG. 8 pin accordingto some embodiments.

FIGS. 66A and 66B illustrate different views of an alternative FIG. 8pin according to some embodiments.

FIGS. 67A-67G illustrate different views of a four-pin multi-pieceimplant according to some embodiments.

FIGS. 68A-68F illustrate different views of an alternative multi-pieceimplant according to some embodiments.

FIGS. 69A-69C illustrate different views of an alternative multi-pieceimplant according to some embodiments.

FIGS. 70A-70D illustrate different views of an alternative multi-pieceimplant according to some embodiments.

FIGS. 71A-71C illustrate different views of an alternative multi-pieceimplant according to some embodiments.

FIGS. 72A-72D illustrate different views of an alternative multi-pieceimplant according to some embodiments.

FIGS. 73A-73D illustrate different views of an alternative multi-pieceimplant according to some embodiments.

FIGS. 74A-74D illustrate different views of an alternative multi-pieceimplant according to some embodiments.

FIGS. 75A-75D illustrate different views of an alternative multi-pieceimplant according to some embodiments.

FIGS. 76A-76D illustrate different views of an alternative multi-pieceimplant according to some embodiments.

FIGS. 77A-77E illustrate different views of an alternative multi-pieceimplant according to some embodiments.

FIGS. 78A-78C illustrate different views of an alternative multi-pieceimplant according to some embodiments.

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS

Embodiments of the invention will now be described. The followingdetailed description of the invention is not intended to be illustrativeof all embodiments. In describing embodiments of the present invention,specific terminology is employed for the sake of clarity. However, theinvention is not intended to be limited to the specific terminology soselected. It is to be understood that each specific element includes alltechnical equivalents that operate in a similar manner to accomplish asimilar purpose.

The present application describes intervertebral implants that areconfigured to be implanted in an intervertebral space between twovertebrae. The implants can comprise one or more spacers, cages, wedges,rings, etc. that are insertable into a disc space. The implants canremain in the intervertebral space for an extended period of time andcan assist in interbody fusion processes.

In some embodiments, the intervertebral implants comprise single-pieceor multi-piece spacers. The multi-piece spacers can include two, three,four or more layers that are placed horizontally, vertically, or in anyorientation relative to one another. The spacers can be formed of anumber of different types of materials, including various metals such astitanium and stainless steel, metallic alloys, polymers such as PEEK andcombinations thereof. In other embodiments, the spacers are formed of abone-material, either natural or synthetic. In some embodiments, thebone-material can include allograft bone, autograft bone, xenograft boneor combinations thereof. The material for such allograft spacers can betaken, for example, from a diaphysis of a long bone.

FIGS. 1-19 illustrate various embodiments of multi-piece spacers havinglayers with multiple features according to some embodiments. While thedifferent layers of material can be held together using an adhesive, inmost of the illustrated embodiments, a fixation device, such as a screw,pin or interference fit device is used to secure the layers together. Insome embodiments, the fixation device can be inserted into a bore holeformed through one or more layers of the implant.

FIG. 1 illustrates a multi-piece implant 10 comprised of two layers 12,14 of material. Each of the layers 12, 14 has a mating face 22, 24. Bothmating face 22 and 24 are illustrated as flat. When the two layers 12,14 are pressed and secured together, they form an intervertebral implantthat can be inserted into a vertebral space. In some embodiments,additional layers can be attached to layers 12, 14, thereby forming animplant with more than two layers. The advantage of having multi-pieceimplants is that the implants can be sized accurately using more or lesslayers to fit within an intervertebral space along different levels ofthe spine for patients of different sizes.

Each of the layers 12, 14 has two vertical bore holes 80, 82 formedtherein. Layer 12 has vertical bore holes 80 a, 82 a, while layer 14 hasvertical bore holes 80 b, 82 b. The vertical bore holes 80 a, 82 a inlayer 12 correspond with and align with the vertical bore holes 80 b, 82b in the other layer 14, thereby forming the two continuous bore holes80, 82 through the implant. The bore holes 80, 82 are configured toreceive a fixation device, such as a pin or screw, to secure the firstlayer 12 to the second layer 14. For purposes of this application, theterm “bore hole” can refer to a bore hole through a single layer, or acontinuous bore hole formed by multiple bore holes formed throughmultiple layers.

The bore holes 80, 82 in FIG. 1 extend from a superior face 5 (e.g., thetop surface of representative layer A) to an inferior face 6 (e.g., thebottom surface of representative layer B). Each of these faces 5, 6 areconfigured to contact a vertebral body, such as an adjacent superior andinferior vertebral body. In other embodiments, the bore holes 80, 82need not extend all the way through a superior face 5 and an inferiorface 6. For example, the bore holes can be blind bore holes, in which atleast one side of the bore hole is blocked or enclosed, as shown in FIG.32B. In other words, for a blind bore hole, at least one of the openingsis covered or enclosed. Alternatively, the bore holes can extend from atop or bottom surface into a side surface, such they will not extendcompletely through from a superior face to an inferior face, as shown inFIG. 42.

FIG. 2 also illustrates a multi-piece implant 10 comprised of two layers12, 14, of material. While the multi-piece implant 10 has flat faces, asin the previously described implant, the implant 10 in FIG. 2 includestwo diagonal bore holes 86, 88 instead of two vertical bore holes. Thetwo diagonal bore holes 86, 88 are formed from bore holes 86 a, 88 a inlayer 12 that extend continuously with the bore holes 86 b, 88 b inlayer 14. As shown in FIG. 2, the bore holes 86, 88 extend through theimplant from a superior face 5 to an inferior face 6. In otherembodiments, the bore holes can extend through an implant from aposterior face to an anterior face, or through an implant from a firstsidewall to a second sidewall.

FIG. 3 illustrates a single layer 12 of a multi-piece implant 10 havingvertical bore holes 80, 82 and a mating face 8 comprising awaffle-pattern. The vertical bore holes 80, 82 are configured to receivea fixation device for securing the layer to a second layer 14, shown inFIG. 4.

As shown in FIG. 3, the layer 12 can include a mating face 33 thatincludes a plurality of square or rectangular protrusions 38. Theprotrusions 38 form a waffle-pattern on the face 33 that is capable ofmating with a complementary face 36 of another layer 14, as shown inFIG. 4. In other embodiments, the protrusions 38 are not square orrectangular, but are of various other shapes, such as tear-shaped ortrapezoidal.

FIG. 4 illustrates a layer 14 that is complementary to the layer 12. Thelayer 14 includes a complementary face 36 that also includes square orrectangular protrusions 38. The protrusions 38 in the first layer 12 fitinto the voids formed between the protrusions 38 in the second layer 12,thereby forming an interlocking implant. In other words, the wafflepattern on the mating face 36 of layer D is configured to fit andcomplement the waffle pattern on the mating face 33 of layer C, therebyforming a two layer spacer that can be inserted into an intervertebralspace. As shown in FIGS. 3 and 4, vertical pin holes 80, 82 can extendthrough the implant 10.

The waffle pattern on the layer can mate with one or more complementarypatterns on other layers, such that two layers can be convenientlymated. As shown in FIG. 3, the waffle pattern is formed of square and/orrectangular formations that have edges. However, in other embodiments,the waffle pattern can be formed by other formations of differentgeometrical shapes, such as triangular protrusions.

FIG. 5 is a cross-sectional view of a multi-layered implant 10 havinglayers 12, 14 with mated waffle faces according to some embodiments.Layer 12 includes a mating face 33 with square or rectangularprotrusions that complements the mating face 33 of layer 14. As shown inFIG. 5, the multi-layered implant 10 includes diagonal bore holes 86, 88for receiving one or more fixation devices.

FIG. 6 illustrates a layer 12 of a multi-piece implant 10 having twovertical bore holes 80, 82. The layer in FIG. 6 includes a mating face33 having protruding features comprising multiple block features 39 inparallel to one another. Advantageously, the blocks 39 extend from oneside of the implant to another, thereby forming a mating surface that iscontinuous throughout a length of the side of the implant. While theblocks 39 are illustrated as being of similar size and evenlydistributed, in other embodiments, the blocks 39 can be of differentsize and or distributed unevenly along the length of the spacer.

FIG. 7 illustrates a layer 14 of a multi-piece implant designed tocorrespond and mate with the layer 12 in FIG. 6. The representativelayer F in FIG. 7 includes a mating face 37 having multiple blockfeatures 39 in parallel that is designed to interlock with the layer inFIG. 6. The layer in FIG. 7 also includes two vertical bore holes thatare designed to match with the vertical bore holes in FIG. 6 to form twocontinuous bore holes that extend through implant 10.

FIG. 8 illustrates a cross-sectional view of a multi-piece implant 10formed of two layers 12, 14. Each of the layers 12, 14 has a faceincluding a plurality of block features 39, as shown in FIGS. 6 and 7.The two layers 12, 14 include a pair of diagonal bore holes 86, 88 thatextend through the implant.

FIGS. 9A and 9B illustrate different views of a multi-piece implant 10formed of two interlocking layers 12, 14 according to some embodiments.Layer 12 includes a shaped “dovetail” groove 42 designed to receive acomplementary mating feature 44 protruding from a surface of layer 14.Advantageously, the mating feature 44 is curved, which helps to securelyinterlock layer 14 into layer 12, thereby forming a secure implant.

As shown in the figures, a pair of bore holes can be formed through theimplant 10. The bore holes can be vertical bore holes 80, 82, as in FIG.9A, or diagonal bore holes 86, 88, as in FIG. 9B. In other embodiments,combinations of vertical and diagonal bore holes are also possible.

FIGS. 10A-10C illustrate different views of a multi-layered implanthaving a mating interface comprising waffle-pattern features accordingto some embodiments. FIG. 10A illustrates an upper layer 12 having abottom mating face comprised of a plurality of square or rectangularprotrusions 38 with grooves in between that form a waffle-pattern. FIG.10B illustrates a lower layer 14 having an upper mating face includingsquare or rectangular protrusions 38 and grooves in between that isdesigned to complement the mating face of the upper layer 12. Themulti-layered implant can include vertical bore holes 80, 82, as shownin FIGS. 10A and 10B, or diagonal bore holes, as shown in FIG. 10C, forreceiving a fixation member.

FIGS. 11A-11C illustrate different views of one or more layers of amulti-layered implant 10 having a mating interface comprisinggeometrical inserts according to some embodiments. FIG. 11A illustratesrepresentative layer I_(b), which includes a mating face 33 having oneor more cylindrical inserts 52 protruding from a surface. Thecylindrical inserts 52 can be inserted into apertures 53 of acorresponding mating face, as shown in FIG. 11B. The cylindrical insertsadvantageously serve as pegs that help to maintain and secure themultiple layers of the multi-layered implant together before and duringimplant.

FIG. 11C illustrates an alternative layer 12 of a multi-layered implant10 having a mating interface comprising differently shaped geometricalinserts 38. The geometrical inserts 38 resemble square or rectangularfeatures (similar to that shown in FIG. 4), and can be inserted into oneor more apertures on a face of a complementary layer. As shown in FIG.11C, the layer 12 also includes one or more block features 39 thatextend along a height of the layer 12. By combining different engagingfeatures, such as the geometrical inserts 38 and the block features 39,this strengthens the ability to interlock two layers of a multi-layeredimplant, thereby helping to secure the implant during use.

FIGS. 12A-12C illustrate different views of a multi-layered implantincluding horizontal bore holes according to some embodiments. FIG. 12Aillustrates a layer 12 having one or more horizontal bore holes 94, 96that can be axially aligned with one or more horizontal bore holes 94,96 in a complementary layer 14 (shown in FIG. 12B). The mating face 33of layer 12 also comprises a plurality of channels or grooves 40 thatare designed to receive complementary features (e.g., block features 39)that protrude from the mating face 37 of layer 14.

FIG. 12C illustrates a cross-sectional view of an implant 10 having twolayers 12, 14 mated together and including horizontal bore holes 94, 96.The horizontal bore holes 94, 96 extend from an anterior side 7 to aposterior side 8 of the implant 10.

FIGS. 13A-13C illustrate different views of a multi-layered implantincluding diagonal bore holes 98, 99 according to some embodiments. Thediagonal bore holes 98, 99 extend from an anterior face 7 to a posteriorface 8. As shown in FIG. 13A, the multi-layered implant can include afirst layer 12 having a first mating face 33 including one or moregrooves for mating with a second mating face 36 of a second layer 14having one or more protruding features. Alternatively, as shown in FIG.13B, the multi-layered implant 10 can include a first layer 12 having aflat mating face 22 and a second layer 14 having a flat mating face 24that form an interface. In yet another embodiment, as shown in FIG. 13C,the multi-layered implant 10 can include a first layer 12 having a firstmating face with a block feature 39 that is capable of being insertedinto a groove 40 formed in a second mating face of a second layer 14.

FIG. 14 is a top perspective view of a layer 12 of a multi-layeredimplant 10 having receiving windows 104 according to some embodiments.The receiving windows 104 are configured to receive one or moreprotruding features from a corresponding layer (not shown).Advantageously, the windows 104 have a sufficient height and width toaccommodate a number of differently shaped protruding features. Forexample, while the windows 104 are rectangular shaped and canaccommodate complimentary rectangular features, the windows 104 can alsoaccommodate one or more cylindrical features. As shown in FIG. 14, thelayer 12 also include vertical bore holes 80, 82 and a horizontal borehole 101 that extends along a length of its longitudinal axis. Thecombination of different oriented bore holes advantageously allows forfixation members (e.g., pins) to be placed in the most desirable areasto support the mating of the different layers of the implant.

FIG. 15 is top perspective view of a complementary layer 14 to the layer12 in FIG. 14. Layer 14 includes two large rectangular inserts 106, 108that can fit within the windows 102, 104 of the layer 14. The sides ofthe inserts 106, 108 can be flush against the sidewalls of the windows102, 104. As shown in FIG. 15, layer 14 can include a horizontal borehole 94 that is aligned along a length of a width of the layer 14.

FIG. 16 illustrates different views of a multi-layered implant 10including a layer 12 with a mating face including protruding angledfeatures 111 according to some embodiments. The protruding angledfeatures 111 can fit into grooves 40 that are formed in a second layer14, thereby forming a secure implant. In some embodiments, the grooves40 are angled to complement the angled features 111. In otherembodiments, the grooves 40 are not angled and simply receive andmaintain the angled features 111 therein.

FIG. 17 is a top perspective view of a layer 12 of a multi-layeredimplant 10 comprising block features 39 according to some embodiments.The block features 39 are configured to be received in grooves 40 formedin a complementary layer 14 (shown in FIG. 18).

FIG. 18 is a top perspective view of a complementary layer 14 to thelayer in FIG. 17. Layer 14 includes a plurality of grooves 40 forreceiving the block features 39. In addition, as shown in FIG. 18, thevertical bore holes 80, 82 need not be symmetrical along the width ofthe layer 14 body. One vertical bore hole 80 extends through a groove40, while the other vertical bore hole 82 extends through a walladjacent to the groove 40.

FIG. 19 is a cross-sectional view of a multi-layered implant 10 havingtwo layers 12, 14 with diagonal bore holes 86, 88 formed therein. Thediagonal bore holes 86, 88 extend through the interface formed by twofaces of layers 12, 14.

FIGS. 20A-31F illustrate different implants having superior and/orinferior faces with surface features, such as teeth or ribs. While suchimplants are illustrated as being single-bodied, in some embodiments,the spacers are multi-pieced and can include any of the matingfeatures/bore-holes described above. In addition, in some embodiments,the superior and inferior faces can be straight and substantiallyparallel to one another. In other embodiments, the superior and/orinferior faces can be curved (e.g., convex or concave). In addition, insome embodiments, each of the illustrated implants can have bodies thatare angled to reflect the natural lordosis in a spine. In someembodiments, the implant bodies have angles between 2 degrees and 50degrees, or 1 degree and 25, degrees relative to an axis that runsthrough the body of the implant, such as a midplane.

FIGS. 20A-20D illustrate different views of an implant 200 having teeth232 according to some embodiments. The implant 200 can be inserted, forexample, in the cervical area of a spine. The implant 200 includes aconcave surface 206 in opposition to a convex surface 204 separated by apair of sidewalls 208, 209. The implant 200 includes a superior face 216and an opposing inferior face 218, which are substantially parallel. Inother embodiments, the superior face 216 and/or inferior face 218 can becurved or angled such that the two faces are not substantially parallel.

The superior and/or inferior faces 216, 218 can include a plurality ofteeth 232 for providing a friction surface against adjacent vertebrae.In some embodiments, the teeth 232 of similar height, while in otherembodiments, the teeth 232 can have varying height across the body ofthe implant. The teeth can be three-sided, four-sided, six-sided or anyother geometrical configuration. In some embodiments, the teeth aresaw-tooth shape and include at least one surface that is substantiallyperpendicular to a surface of the implant.

A central hole 219 can be formed in the body of the implant 200 toreceive a plug 210, such as in FIG. 20B. While the central hole 219 isillustrated as being circular, in other embodiments, the central hole219 is square, rectangular, trapezoidal, tear shaped, or any othershape. In some embodiments, the central hole 219 has a geometryincluding one or more edges. In some embodiments, the implant 200 bodycan be formed of cortical material, while the inner plug 210 can beformed of cancellous material.

As shown in FIGS. 20B and 20D, the implant 200 can include one or moreslots 260 configured to be grasped by an insertion instrument. While theslots 260 are formed on the sidewalls 208, 209 of the implant 200, inother embodiments, slots 260 can be formed on other parts of the implantbody, such as on a superior 216 and/or inferior surface 218.

In addition to the features discussed above, the implant 200 can includea leading edge 240. In some embodiments, the leading edge 240 serves asdistraction surface that helps to distract one or more vertebral bodieswhile the implant 200 is inserted into a disc space. In someembodiments, the leading edge 240 comprises smooth, tooth-free zonesthat are formed on the superior 216 and/or inferior surface 218 of theimplant 200. As shown in FIG. 20D, the leading edge 240 can be angled ortapered such that the implant 200 is bullet-nose or wedge shaped.

FIGS. 21A-21D illustrate different views of an alternative implant 300having teeth 232 according to some embodiments. The implant 300 can beinserted, for example, in a lumbar region of the spine via an anteriorapproach. The implant 300 can include two convex surfaces 332, 334 withsidewalls 308, 309 formed in between. The implant 300 further includes asuperior surface 316 and an inferior surface 318. As shown in FIG. 21B,the superior surface 316 and/or the inferior surface 318 can have someslight curvature. In some embodiments, both the superior surface 316 andthe inferior surface 318 include one or more teeth 232 to assist inproviding a frictional zone against adjacent vertebral bodies.

As shown in FIG. 21A, the implant 300 can include a central hole 319.Unlike the central hole 219 in FIG. 20B, the central hole 319 in thepresent implant 300 is not filled with a cancellous bone plug. In someembodiments, the central hole 319 can be configured to receive bonegraft material, which can assist in spinal fusion in between twovertebrae.

In some embodiments, the implant 300 can also include a leading edge 340which is formed at the convergence of the superior surface 316 andinferior surface 318. The leading edge 340 can comprise smooth,tooth-free zones that serve to advantageously distract vertebral bodiesduring implantation. As shown in FIG. 21B, leading edge 340 can beangled such that a portion of the implant 300 is bullet-nosed or wedgeshaped.

In some embodiments, the implant 300 can also include slots 324 that areformed on the superior and/or inferior surfaces 316, 318 of the implant.In some embodiments, an insertion instrument can be used to grip theslots 324, thereby helping to facilitate the insertion of the implant ina vertebral space. In other embodiments, the slots 324 can receive oneor more portions of a distraction instrument to assist in thedistraction of adjacent vertebrae during implantation. In someembodiments, the insertion instrument can be an instrument separate froma distraction instrument. In other embodiments, the insertion instrumentcan include a distractor function, and can advantageously distractvertebrae while simultaneously inserting an implant.

FIGS. 22A-22D illustrate different views of an alternative implant 400having teeth 232 according to some embodiments. The implant 400 can beinserted, for example, in a lumbar region of the spine via atransforaminal approach. The implant includes a superior surface 416 andan inferior surface 418 that include teeth 232. As shown in FIG. 22A,the teeth need not extend entirely across the body of the implant 400;rather, a tooth-free region can be formed around the teeth 232. Theimplant 400 can include a convex surface 404 opposite a concave surface406. The convex surface 404 and concave surface 406 can be substantiallyparallel, while in other embodiments, the convex surface 404 and concavesurface 406 are not substantially parallel. As shown in FIG. 22C, theimplant 400 can have a rectangular cross-sectional area.

In some embodiments, the implant 400 can include a slot 260. The slot260 can be formed on the convex surface 404 and or concave surface 406,and can be configured to receive an insertion instrument to assist indelivery of the implant into an intervertebral space. In addition, as inpreviously discussed implants, the implant 400 can include a tooth-free,leading edge 440.

FIGS. 23A-23E illustrate different views of an alternative implant 500having teeth according to some embodiments. The implant 500 can beinserted, for example, in a lumber region of the spine via a posteriorapproach. The implant 500 can have a substantially flat superior surface516 that opposes a substantially flat inferior surface 518. In someembodiments, the implant 500 can be flat in a medial-lateral direction,but can include a radius of curvature in the anterior-posteriordirection. Each of the superior surface 516 and/or inferior surface 518can include teeth 232 for contacting vertebral bodies. As shown in FIG.23C, the implant 500 can also include a leading edge 540.

As shown in FIGS. 23B and 23C, the implant 500 can include a large slot560 for receiving a portion of an insertion instrument. In someembodiments, the slot 560 advantageously extends along a majority of thelength of the implant 500, thereby creating a large surface area forreceiving a portion of an insertion instrument.

FIGS. 23D and 23E illustrate alternative rear views of the implant 500.As shown in these figures, in some embodiments, a posterior portion ofthe implant 500 can have angled, tapered surfaces 582 that converge at aflat face 590. In some embodiments, the posterior face 590 can have alength and height that is substantially different from the length andheight of a face along an anterior portion of the implant 500.

FIGS. 24A-24E illustrate different views of an alternative implant 600according to some embodiments. The implant 600 can be inserted, forexample, in a lumbar region of the spine via a posterior approach. Theimplant 600 shares many similar features as the implant in FIG. 23A,including a superior face 616 and inferior face 618 including teeth 232,a leading edge 640 that is angled, and a slot 660 that extendssubstantially along a majority of the length of the body of the implant600.

FIGS. 25A-25E illustrate different views of an alternative implant 700having teeth 232 according to some embodiments. The implant 700 can beinserted, for example, in a lumbar region of the spine via a lateralapproach. The implant includes a superior face 716 and an inferior face718, each including a plurality of teeth 232 formed thereon. As shown inFIG. 25C, the superior face 716 and inferior face 718 can besubstantially flat and planar, while in other embodiments, the superiorface and/or inferior face can be curved. The implant 700 can alsoinclude a tooth-free, leading edge 740.

In some embodiments, the implant 700 can include a hole 719 extendingfrom a superior face 716 to an inferior face 718, as shown in FIG. 25A.While the hole 719 is illustrated as a polygon having one or more curvedor straight edges, in other embodiments, the hole 719 is round. As shownin FIG. 25A, the hole 719 can include two sidewalls 722 and 723 thatextend along a majority of the length of the implant 700. By having sucha lengthy hole, bone graft can advantageously be inserted and grow alonga substantial portion of the implant, thereby aiding in bone fusionprocesses. In some embodiments, the two sidewalls 722, 723 substantiallymatch the sidewalls of the implant 700.

In some embodiments, as shown in FIG. 25E, implant 700 can include oneor more slots 724 on a superior surface 716 and/or inferior surface 718.The slots 724 can be configured to receive one or more instruments, suchas insertion or distraction instruments, to assist in the implantationof the implant 700.

In contrast to the implants in FIGS. 20A-25E, the implants in FIGS.26A-31F include ribs or ridges, rather than teeth. These implants arenow discussed.

FIGS. 26A-26D illustrate various embodiments of an implant 1200 havingridges 236. The implant 1200 can be inserted, for example, in a cervicalregion of the spine. The implant 1200 can include a convex surface 204and a concave surface 206 with sidewalls therebetween.

The implant 1200 can include a plurality of ridges 236 formed on asuperior surface 216 and/or inferior surface 218. In some embodiments,the ridges 236 are formed continuously across a surface of the implant1200 (as shown in FIG. 26A), whereas in other embodiments, the ridges236 are separated and have spaces in between. The implant 1200 caninclude a tapered leading edge 240, thereby forming a bullet-nose orwedge-shaped portion.

In some embodiments, as shown in FIG. 26B, the convex surface 204 cancomprise a posterior face having a height H2. The concave surface 206can also comprise an anterior face having a similar height H2. Oneskilled in the art will appreciate that the convex surface 204 can alsobe considered an anterior face, while the posterior face can beconsidered an anterior face, depending on the position of a userrelative to the spine. In other embodiments, the anterior face andposterior face of the implant 1200 can be of differing heights.

FIGS. 27A-27E illustrate various embodiments of an alternative implant1300 having ridges 236. The implant can be inserted, for example, in alumbar region of the spine via an anterior approach. The implant 1300includes a superior surface 1316 and an inferior surface 1318, eachcovered in part by one or more ridges 236. As shown in FIG. 27A, theimplant 1300 can include a leading end 1340 which is smooth and notcovered by ridges. In addition, the implant 1300 can include one or moreslots 1324 that can be grasped by a distraction and/or insertioninstrument to assist in inserting the implant into a vertebral space.The implant 1300 also includes a hole 1319 for receiving graft material.While the hole 1319 is illustrated as circular, in other embodiments,the hole 1319 is square, rectangular, trapezoidal or any other shape.

In some embodiments, as shown in FIG. 27B, the superior surface 1316 andthe inferior surface 1318 are substantially parallel. In otherembodiments, the superior surface 1316 and/or the inferior surface 1318can be partially curved and/or angled (lordotic), such that the twosurfaces are not substantially parallel. In some embodiments, ananterior face of the implant 1300 can be of similar height H2 to aposterior face of the implant 1300, as shown in FIG. 27B.

As shown in FIG. 27D, the ridges 236 formed on the implant can besubstantially continuous. That is, there is a minimal if any gap orspace between adjacent ridges. In other embodiments, the ridges 236 canbe separated by a space and are not continuously formed.

FIGS. 28A-28E illustrate various embodiments of an alternative implant1400 having ridges 236 that can be used, for example, in a lumbar regionvia a transforaminal approach. The implant 1400 includes a firstsidewall 1404 that is opposite a second sidewall 1406. The firstsidewall 1404 includes two concave surfaces 1414 and 1418. The secondsidewall 1406 includes a third concave surface 1406. Advantageously,with the multiple concave surfaces, the implant 1400 is of a geometrythat is desirable for different approaches, such as a transforaminalapproach.

In addition to the features discussed above, the implant 1400 can alsoinclude one or more slots 1460 formed on one or more of the sidewalls1404, 1406. The one or more slots 1460 can be grabbed by an insertioninstrument.

FIGS. 29A-29E illustrate various embodiments of an alternative implant1500 having ridges 236 that can be used, for example, in a lumbar regionof the spine via a posterior approach. The implant includes a pair ofside channels 1560 for receiving an insertion instrument.Advantageously, as shown in FIG. 29A, the side channels 1560 can extendalong a majority of the length of the implant 1500, thereby providing alarge grasping area for the insertion instrument.

FIGS. 30A-30F illustrate various embodiments of an alternative implant1600 having ridges 236 that can be used, for example, in a lumbar regionof the spine via a posterior approach. The implant is similar to thatshown in FIGS. 29A-29E, but includes a different footprint. While someof the embodiments illustrate an implant 1600 having a superior surface1616 and an inferior surface 1618 that are parallel or minorly curved(FIG. 30B), other embodiments illustrate an implant 1600 having asuperior surface 1616 and an inferior surface 1618 that are noticeablycurved and form a lordotic structure (FIG. 30F).

FIGS. 31A-31F illustrate various embodiments of an implant 1700 havingridges 236 that can be used, for example, in a lumbar region via alateral approach. In some embodiments, the implant can include twoparallel sidewalls 1706 and 1708 (FIG. 31A), while in other embodiments,the implant can include a straight sidewall 1706 that opposed a convexsidewall 1708 (FIG. 31E). In addition, in some embodiments, the implant1700 can have substantially parallel superior and inferior surfaces1716, 1718 (FIG. 31D), while in other embodiments, the implant 1700 canhave a lordotic angled surface (FIG. 31F).

FIGS. 32A-44 illustrate additional embodiments of multi-piece implantassemblies. These embodiments are now described and are meant only to beillustrative. For example, while the implant assemblies in FIGS. 32A-44do not illustrate horizontal bore holes, these implants may also includethese features.

FIGS. 32A-32C illustrate embodiments of a multi-piece implant 10 havingangled and/or curved mating faces 27, 28. Layer 12 includes an angledmating face 27 that mates with angled mating face 28 of layer 14.Advantageously, by having complementary features, this helps to keep thetwo layers 12, 14 of the implant 10 together.

As shown in FIG. 32B, diagonal bore holes 86 and/or vertical bore holes80 can be introduced through the implant 10. The bore holes can extendcomplete through the implant, from a superior surface to an inferiorsurface. Alternatively, the bore holes can be blind, wherein a side ofthe bore hole is blocked by a surface of one of the layers 12, 14. Byhaving blind bore holes, this advantageously prevents inadvertentremoval or back-out of fixation members that are inserted through theholes.

FIGS. 33A-33C illustrate some embodiments of a multi-piece implant 10having zig-zagged mating faces 27, 28. Layer 12 includes a firstzig-zagged mating face 27, while layer 14 includes a second zig-zaggedmating face 28. As shown in FIG. 33C, each of the zig-zagged matingfaces 27, 28 can include stepped features. The zig-zagged mating faces27 and 28 complement each other, thereby helping to form a securemulti-piece implant.

As shown in FIG. 33B, the implant 10 can also include diagonal boreholes 86 and/or vertical bore holes 80 that extend across the interfaceof the two bodies 12 and 14. The bore holes 86 and 88 can extendcompletely through a superior surface to an inferior surface, oralternatively, can be blind bore holes as discussed above.

FIGS. 34A-34C illustrate some embodiments of a multi-piece implant 10having curved mating faces 27, 28. As shown in the figures, the matingfaces 27, 28 of the layers can be continuously curved without having anyparticular edge. The layers 12, 14 in the present embodiments can alsoinclude diagonal and/or vertical bore holes that are may or may not beblind.

FIGS. 35A-35C illustrate some embodiments of a multi-piece implant 10having straight, jagged mating faces 27, 28. As shown in FIG. 35C, layer12 can have a mating face 27 that is comprised of a single jagged step.Likewise, layer 14 can have a mating face 28 that is comprised of acomplementary jagged step such that when layer 14 is pressed againstlayer 12, the two layers form a multi-piece implant. As in previouslydiscussed embodiments, the implant 10 can include a variety of differentbore holes that are continuous from a superior surface to an inferiorsurface, or blind.

FIGS. 36A-36C illustrate some embodiments of a multi-piece implant 10having at least three layers 12, 14, 15 with flat mating faces. Layer 12includes a flat mating face 27 that forms an interface with flat matingface 28 of layer 14, while layer 15 includes a flat mating face 30 thatforms an interface with flat mating face 29 of layer 14. In otherembodiments, less than three layers (e.g., two) or greater than threelayers (e.g., four or five) having flat mating faces can form a similarmulti-piece implant.

As shown in FIG. 36B, the multi-piece implant 10 can incorporate a borehole such as vertical bore hole 80. In some embodiments, the bore hole80 will not extend through either a superior face or an inferior face,but rather, can have two blind ends, as shown in FIG. 36B.Advantageously, by having two blind ends, the bore hole 80 will be ableto fix the multiple layers together, but will be prevented frominadvertently backing out of the implant during use.

FIGS. 37A-37C illustrate some embodiments of a multi-piece implant 10having layers with mating faces 27, 28 including a pair of exteriorflats followed by a curved inner surface. As shown in FIG. 37A, layer 12can include a mating face having a pair of exterior flats 31 and acurved inner surface 32 there between. Layer 14 can include a matingsurface 28 that is complementary to the mating face 27, wherein it alsoincludes flats and a curved inner surface. The multi-piece implant caninclude diagonal and vertical bore holes of different variations asshown in FIG. 37B.

FIGS. 38A-38C illustrate some embodiments of a multi-piece implant 10having a pair of bore holes 80, 82. As shown in FIG. 38B, each of thebore holes 80, 82 is blind. Accordingly, from a top view, only one borehole 80 is visible in the superior surface, as shown in FIG. 38A. Thebores 80, 82 each cross the interface formed by the contacting matingfaces 27 and 28.

FIG. 38B illustrates a cross-sectional view of the implant 10 accordingto some embodiments. As shown in this view, the interface between thelayer 12 and layer 14 is a flat surface. However, in alternative views,as show in the cross-sectional view of the implant 10 in FIG. 38C, theinterface between layer 12 and layer 14 can also be curved in someportions.

FIGS. 39A-39C illustrate some embodiments of an alternative multi-pieceimplant 10 having a pair of bore holes 80, 82. As shown in FIG. 39B,each of the bore holes 80, 82 is blind. Accordingly, from a top view,only one bore hole 82 is visible in the superior surface, as shown inFIG. 39A. The bores 80, 82 each cross the interface formed by thecontacting mating faces 27 and 28.

FIG. 39B illustrates a cross-sectional view of the implant 10 accordingto some embodiments. As shown in this view, the interface between thelayer 12 and layer 14 is not only flat, but also includes somecurvature. The curved features of the interface are also shown in FIG.39C.

FIGS. 40A-40C illustrate some embodiments of a multi-piece implant 10having a pair of bore holes 80, 82. The implant 10 is composed of twolayers 12, 14. Each of the layers has a mating face 27, 28 that has ahorizontally straight portion and a vertically straight portion, asshown in FIG. 40B. From a different cross-sectional view shown in FIG.40C, the mating interface between layer 12 and layer 14 is flat.

FIGS. 41A-41C illustrate some embodiments of a multi-piece implant 10having a pair of bore holes 80, 82. The implant is composed of twolayers 12, 14, each having a flat mating face 27, 28. The implant 10includes two vertical bore holes 80, 82.

FIGS. 42A-42C illustrate some embodiments of a multi-piece implant 10having a pair of diagonal bore holes 86, 88. Both of the bore holes 86,88 are blind in that they do not extend completely through an implant.The implant 10 includes two layers 12, 14 having flat mating faces 12,14, as shown from different viewpoints in FIGS. 42B and 42C.

FIGS. 43A-43C illustrate some embodiments of a multi-piece implant 10having a pair of diagonal bore holes 86, 88. In contrast to the previousembodiment, the current embodiment includes two layers 12, 14 having amating interface that is angled, as shown in FIG. 43B. In addition, insome embodiments, portions of the mating interface can be curved, asshown in FIG. 43C.

FIGS. 44A-44C illustrate some embodiments of a multi-piece implant 10having an inner concentric member 97. As shown in FIG. 44A, the implant10 is comprised of two separate layers 12 and 14. Each of the layers 12and 14 includes an inner hole that aligns to form a single through holewhen the two layers are pressed together, as shown in FIG. 44C. An innerconcentric member 97 can be received through the single through hole,thereby advantageously helping to hold the implant in one piece. Thisdesign advantageously avoid the use of fixation members (e.g., pins),which can protrude from the body of the implant and/or inadvertentlycome loose within the system. In other embodiments, fixation members canbe incorporated into the design.

FIG. 45 is a cross-sectional view of a multi-piece implant 10 having apair of bore holes 86, 88 according to some embodiments. As shown in theillustration, the multi-piece implant 10 is composed of two layers 12,14, each of which includes a v-shaped mating face 27, 28.

FIG. 46 illustrates a multi-piece implant 10 having concentriccomponents 1810, 1820 according to some embodiments. The implant 10includes a first concentric outer member 1810 and a second concentricinner member 1820 that fits therein. In some embodiments, the innermember 1820 is slidable within the outer member 1810, thereby forming animplant for implanting in an intervertebral space.

FIG. 47 illustrates a multi-piece implant 10 having an insertablecomponent 1920 according to some embodiments. The implant 10 comprises afirst layer 1910 including a slot 1927 that extends along a substantialportion of its width. The slot 1910 is configured to receive a secondinsertable layer 1920 that fits therein, thereby forming a multi-pieceimplant for implanting in an intervertebral space.

FIG. 48 illustrates an alternative multi-piece implant 10 having aninsertable component 2020 according to some embodiments. The implant 10comprises a first member 2010 that includes an open chamber 2017. Theopen chamber 2017 includes one or more slots or recesses 2019 formedtherein to receive an insertable component 2020. As shown in the figure,the insertable component 2020 can comprise a planar structure that isslidable into a corresponding recess 2019. While the illustratedembodiment shows a chamber 2017 having a single recess 2019corresponding to a single insertable component 2020, in otherembodiments, the chamber 2017 can include more than one slot. In someembodiments, the insertable component 2020 can be pinned to the openchamber 2017, thereby helping to further secure the multi-piece implantfor use.

FIGS. 49A and 49B illustrate different embodiments of a multi-pieceimplant 10 having components with engaging surfaces. FIG. 49Aillustrates two separate multi-piece implants 10 having components withengaging surfaces. Dashed lines represent optional pin holes. In someembodiments, the implant 10 can include a first component 2112 having acut corner that engages a second component 2114 having a different cutcorner to form a single-bodied implant. In other embodiments, theimplant 10 can include a first component 2112 having a cut corner, asecond component 2114 having a different cut corner, and a thirdcomponent 2116 that completes the form implant 10.

FIG. 49B illustrates an embodiment of a multi-piece implant 10 havingtwo separate components. The first component 2114 includes a cutrectangular corner, while the second component 2112 comprises a geometrythat fits within the cut rectangular corner of the first component 2114.

FIG. 50 illustrates a multi-piece implant 10 having a connecting platemember 2216 according to some embodiments. The implant 10 can comprisetwo cylindrical members 2210 and 2212. In alternative embodiments, themembers 2210 and 2212 need not be cylindrical, but can be square,rectangular or any other shape. Each of the members 2210, 2212 includeapertures 2213, 2214 for receiving a peg or rod of a connecting platemember 2216. The connecting plate member 2216 advantageously helps tohold the two cylindrical members 2210 and 2212 together, thereby formingan implant that is implantable in a vertebral space.

FIG. 51 illustrates a multi-piece implant 10 having threaded componentsaccording to some embodiments. The implant 10 can comprise a firstcomponent 2312 having an inner threaded section 2322 and a secondcomponent 2324 having a threaded protrusion 2324 that complements theinner threaded section 2322. The threaded components advantageously holdthe implant together prior to, during and after implantation of theimplant 10 in an intervertebral space.

FIGS. 52A and 52B illustrate a multi-piece implant having a concentricinner member according to some embodiments. FIG. 52A illustrates across-sectional view of an implant 10 having a concentric inner member2408 that fits in an outer member 2414, while FIG. 52B shows a top viewof the same implant 10. As shown in FIG. 52B, the outer member 2414includes a central opening for receiving the inner member 2408, whichresembles a ring. One or more bore holes can be formed through the innerand outer members to receive fixation devices for holding the implanttogether. While the bore holes are illustrated as diagonal bore holes86, 88, 96, 98, in other embodiments, vertical and/or horizontal boreholes can be used to receive fixation devices.

FIG. 53 illustrates an insertable member 2515 of a multi-piece implantaccording to some embodiments. The insertable member 2515 resembles ahorse-shoe shape that can be received, for example, in a slot formed ina receiving member (not shown). As shown in this embodiment, variousinserts of different shapes, geometries and sizes can be used to form amulti-layer implant.

FIGS. 54A-54C illustrate an implant having shims according to someembodiments. The implant 10 comprises a body having an opening 2608configured to receive one or more shim members 2611 therein. The implantcan be sized and configured for use in any part of the vertebrae,including the lumbar, thoracic, and particularly, the cervical region.

The implant 10 comprises a body having an opening 2608 that isconfigured to receive bone material therein. The implant 10 can be asingle-piece, or as in prior multi-piece implants described above, theimplant 10 can include multiple layers. In some embodiments, the implantcomprises a first layer 12 and a second layer 14. In other embodiments,the implant can be composed of three, four, five or more layers. Inaddition, while the layers 12 and 14 are stacked vertically, in otherembodiments, the layers can be assembled horizontally or laterally.

As shown in FIGS. 54A-54C, the implant 10 can have a convexly curvedanterior surface 7 and a concavely curved posterior surface 8. Suchcurvature can advantageously help to mimic the natural curvature of thespace. In some embodiments, the convexly curved anterior surface 7 canhave a curvature that is substantially smooth. In other embodiments, asshown in FIG. 54A, the curvature can include flat segments and evenslight edges, so long as the overall surface is substantially curved.One skilled in the art will appreciate that the shape of the implant isnot limited to the convexly curved anterior surface and concavely curvedposterior surface. For example, in some embodiments, the implant 10 willhave a convex surface opposed to a convex surface, or a convex surfaceopposed to a substantially flat surface. In addition, one skilled in theart will appreciate that the terms “anterior” and “posterior” are notlimiting, and that the terms can be used to identify any opposingsurface of the implant.

In some embodiments, the opening 2608 of the implant 10 extends from anupper superior surface to a lower superior surface of the implant. Insome embodiments, the opening 2608 is composed of a first openingthrough the first layer 12 and a second opening through the second layer14. In the illustrated embodiments, a first opening in the first layer12 and a second opening through the second layer 14 can be substantiallyaligned to form the opening 2608. In other embodiments, a first openingin the first layer 12 and a second opening through the second layer 14can be partially aligned and partially off-set.

As shown in FIGS. 54A and 54B, the opening 2608 in the implant 10 issymmetric, and includes a pair of opposing flat surfaces that transitioninto rounded corners. Advantageously, the rounded portions of theopening 2608 are configured to receive one or more shim members 2611therein. While the illustrated embodiments show two shim members, theimplant 10 can also be used with a single shim member, or three, four,five or more shim members.

The shim members 2611 are wedge-like members that are configured to beinserted (e.g., via friction or press-fit) through the opening 2608.Advantageously, insertion of the shim members 2611 into the opening 2608helps to maintain the different layers 12 and 14 together and furtherprovides structural support to the overall implant. In some embodiments,the shim members 2611 are oval or elliptical in shape, although othershapes and geometries are also possible. In addition, as shown in theshim member represented in FIG. 57, the shim members 2611 can include asmall nub or protrusion 2613 that extends outwardly from a generallysmooth, curved surface. The advantage of this nub 2613 is that it allowsthe shim to be more easily retained within the opening 2608 of theimplant 10. In some embodiments, the shim members 2611 are composed ofthe same or similar material as the body of the implant 10. For example,the body of the implant 10 and the shim members 2611 can all be composedof allograft (e.g., cortical) bone. In other embodiments, the shimmembers 2611 are composed of a different material from the body of theimplant 10. For example, the body of the implant 10 can be composed of acortical bone, while the shim members 2611 can be composed of a hardersynthetic material.

In some embodiments, the opening 2608 can be configured to receive theshim members 2611 at an angle relative to an interface of the firstlayer 12 and the second layer 14, as shown in FIG. 54C. Advantageously,by having shim members 2611 that are at an angle to an interface of thefirst layer and the second layer, this can help provide additionalsecurity for securing the first layer to the second layer duringimplantation. However, one skilled in the art will appreciate that theshim members 2611 can also be provided parallel or perpendicular to theinterface of the first layer and the second layer.

FIGS. 55A and 55B illustrate an alternative implant having shimsaccording to some embodiments. The implant 10 is similar to the implantshown in FIG. 54A, but also includes a plurality of ridges 236 onsuperior and/or inferior surfaces thereof. The ridges 236 advantageouslyhelp to grip adjacent vertebral surfaces. As shown in the illustratedembodiments, the ridges 236 can formed on both the body of the spacer10, as well as on the surfaces of the shim members 2611. In alternativeembodiments, the body of the spacer 10 includes ridges, while the shimmembers 2611 do not include ridges. In some embodiments, as shown inFIG. 55B, the ridges 236 can be separated by a planar surface such thatthey are maintained a certain distance from one another. In otherembodiments, as shown in FIG. 56B, the ridges 236 are not separated by aplanar surface between one another. Rather, the ridges 236 arecontinuously formed and in general, do not extend from a planar surface.While the illustrated embodiments show surface texture comprised ofridges, other types of surface texturing can also be provided, includingprotrusions, teeth, and peg members.

FIGS. 56A-56C illustrate an alternative implant having shims accordingto some embodiments. The implant 10 is similar to that shown in FIG.55A, but includes ridges 236 that are not spaced from one another. Theridges 236 in FIG. 56A thus do not extend from a planar surface, butrather are continuously formed across the superior and/or inferior facesof the implant 10. In contrast to the ridges in FIG. 55A that extendfrom a substantially planar surface, in the embodiment in FIG. 56A, theridges themselves comprise the superior and/or inferior surfaces. Inother words, there is no clear planar or base surface from which theridges extend. In some embodiments, the entire superior and/or inferiorfaces of the implant 10 are covered in ridges or some type of surfaceprotrusion. In other embodiments, and as shown in the figures, theridges 236 need not extend across the entire superior and/or inferiorsurfaces, thereby allowing for a ridge-free portion on the surfaces. Insome embodiments, the ridge-free portions of the implant 10 canadvantageously be grasped by an instrument, such as an insertioninstrument, to facilitate insertion or can be used as a distraction end.

In addition, as shown in FIG. 56B, the implant 10 further includes oneor more instrument gripping side channels 2660. In some embodiments, theone or more side channels 2660 comprise a recess having walls withoutadditional openings therein. In other embodiments, the side channels2660 comprise a recess having walls that include additional openings(e.g., scalloped openings) formed therein. Advantageously, an insertioninstrument can be used to grip the one or more side channels, therebyhelping to deliver the implant into a desired surgical space.

FIGS. 58A-58D illustrate an alternative implant for receiving a plugaccording to some embodiments. The implant 10 can have a concave facethat opposes a convex face. In the center of the implant is an opening2608 for receiving a plug 2610. As shown in FIG. 58B, the plug can havean upper flat surface and a bottom angled surface. As shown in FIG. 58D,the implant 10 can be lordotic in order to fit into a desired anatomicalspace.

FIGS. 59A-59D illustrate an alternative implant assembled from two ormore members in series according to some embodiments. The implant 10 canbe assembled from two or more members of cortical bone in series and/orparallel. This advantageously helps to create an implant that is longerand/or wider than a single-piece, natural bone diameter would allow for.In some embodiments, the implant 10 in the present embodiment can beused in a lateral approach; however, one skilled in the art willappreciate that the implant can be used via other approaches as well.Advantageously, the designs described herein are strong enough towithstand a variety of loading situations placed on the implant frominsertion, while providing variability for manufacturing.

As shown in FIG. 59A, the implant 10 can be formed of multiple members(e.g., cortical members) formed in series. In the present embodiment,the implant 10 includes three rings or members of cortical bone 2720,2721, 2722 (e.g., from femoral rings) that are placed in series andattached to one another. Each of the members 2720, 2721, 2722 includesan upper surface and a lower surface having a plurality of ridges toassist in engage adjacent vertebral surfaces. The ridges advantageouslyprevent expulsion of the implant during increased loading on the implant10.

In addition, each of the members 2720, 2721, 2722 advantageouslyincludes its own respective hole or opening 2708, 2709, 2710 forreceiving graft material therethrough. The openings 2708, 2709, 2710 canbe square-shaped with rounded edges. In some embodiments, a bone plug(e.g., cortical or cancellous) can also be provided through the opening.

As shown in FIG. 59A, each of the member 2720, 2721, 2722 can have itsown distinct shape and features. For example, member 2720 can have acurved, tapered leading end 2740 that can advantageously serve as adistraction edge in some embodiments. Member 2721, which is in themiddle of the three members, assumes a different shape (e.g., square)with actual corners. Trailing member 2722 can have curved edges similarto leading member 2720. However, trailing member 2722 need not have atapered edge.

To assemble the members 2720, 2721, 2722 in series and/or parallel,fixation members or bone pins can be inserted through the members. Asshown in FIG. 59B, the bone pins can be inserted through holes 86 thatare formed through the bodies of the members 2720, 2721, 2722. In someembodiments, the bone pins extend across the interface of at least twoof the members 2720, 2721, 2722 to fix the members together. In someembodiments, the bone pins are inserted at an angle or diagonally acrossthe interface of at least two of the members 2720, 2721, 2722, while inother embodiments, the bone pins are inserted vertically. As shown inFIG. 59B, the bore holes 86 for receiving the bone pins can haveopenings that open within one or more slots 2724 formed on the side ofthe members 2720, 2721, 2722. In alternative embodiments, the members2720, 2721, 2722 can be attached to one another via a different means,such as an adhesive. In addition, in some embodiments, the members 2720,2721, 2722 may have complementary mating surfaces that interlock withone another, such as complementary “S” curves or step shapes as shownabove. Any type of fastening mechanism, such as shims, biscuits, orinterlocking “puzzle” features can be used instead of or in addition tothe bone pins described above.

As shown in FIG. 59B, one or more of the members 2720, 2721, 2722 canhave one or more slots 2724 formed on a sidewall thereof. For example,in some embodiments, an extended slot will traverse at least partiallyalong the side of each of members 2720, 2721, 2722. In addition, asecond slot (not shown) can be provided on an opposite side of themembers. In some embodiments, a grasping or insertion instrument can beused to grab and hold the members to thereby deliver the adjoinedmembers to a desired vertebral space.

FIG. 59C shows a front view of the tapered leading end 2740 of theimplant 10. The tapered leading end 2740 can comprise a convex surfaceformed of a substantially flat surface 2742 with adjacent curvedsurfaces 2743, 2744. The adjacent curved surfaces 2743, 2744 transitioninto the sidewalls of the spacer along its longitudinal length.

FIGS. 60A-60D illustrate an alternative implant assembled from two ormore members in series according to some embodiments. In the presentembodiment, the members 2820, 2821, 2822 comprise members made fromcortical bone that are substantially of the same shape. Each of themembers 2820, 2821, 2822 includes opposing convex walls separated bystraight walls. Each member also includes respective graft openings2808, 2809, 2810 for receiving graft material therein. As shown in FIG.60A, each of the members 2820, 2821, 2822 includes at least one borehole 86 extending therethrough. The bore hole 86 through one member iscontinuous with a bore hole through another member so as to allow a bonepin or fastener to be inserted across an interface between two members.In some embodiments, the bore holes 86 are diagonal, while in otherembodiments, the bore holes are vertical or horizontal.

As shown in FIG. 60B, the bore holes 86 can be formed such that members2820 and 2822 have openings through their convex faces. Middle member2821 will not have bore holes 86 that extend through its convex faces.

As shown in FIG. 60C, one or more bone pins 2811 can be inserted throughthe bore holes 86. Advantageously, each interface between members has atleast two bone pins 2811. For example, the interface between member 2820and 2821 has at least two bone pins, while the interface between member2821 and 2822 has at least two bone pins. This advantageously forms asecure locking mechanism that secures the members together. Any of theother attachment mechanisms, such as adhesives or complementary matingfeatures, can also be applied to the present embodiment.

The embodiments in FIGS. 59A-60D provide implants that are strong towithstand loading. In addition, the implants can be assembled in series,and provide desired variability to a surgeon. In some embodiments, theimplants can be preassembled such that a surgeon can pick from a numberof different configurations. In other embodiments, the surgeon canassemble the implants himself prior to performing a surgery. In someembodiments, the implants can comprise cortical bone (e.g., femoralrings) that are attached in series to allow the implant to span themajority of a disc space, thereby providing a larger area for fusion andgreater stability. As the members are advantageously attached in series,the total length of the implant can be increased to cover more surfacearea in an intervertebral space. Cutouts or slots in the implantadvantageously allow the surgeon to use an instrument designed with theimplant to firmly hold and precisely place the implant in a desiredintervertebral space.

FIG. 61 illustrates an alternative implant assembled from two or moremembers in series and in a stacked configuration according to someembodiments. In the present embodiment, four members 2920, 2921, 2922and 2923 are arranged side-by-side. In some embodiments, the members arearranged in series (e.g., member 2920 is arranged side-by-side withmember 2921). Alternatively, the members can be viewed as on the sameplane but stacked. For example, members 2920 and 2921 are stacked on topof members 2922 and 2923. Each of the members includes its own grafthole 2907, 2908, 2909 and 2910. In addition, at least one bore hole 86extends between the interfaces amongst each of the members.

For some implants formed of two or more members, it may be difficult tofind enough purchase through the bone members for using the pinningmethods described above. In addition, under certain circumstances, usingpins as described above can allow undesired rotation of one memberrelative to another. In order to solve these issues, it has been foundthat using one or more compressive pins—particularly in the form of a“FIG. 8” shape—can help secure the two or more members together andreduce undesired rotation between the members.

Advantageously, the use of the compressive pins described herein allowsfor a smaller amount of bone thickness for securing two members togethersince the pin can run parallel to assembled faces rather thanperpendicular. This allows the compression pin to make contact with alarger surface area along the assembly places in a shorter distance andeliminates any potential axis of ration between assembled parts.

FIGS. 62A and 62B illustrate different views of an alternative implantwith a FIG. 8 pin according to some embodiments. FIG. 62A shows theimplant 10 assembled, while FIG. 62B shows the implant 10 unassembled.The implant 10 comprises a body 3000 formed of at least two sub-bodiesor members 3021, 3022 formed of bone. Each of the members 3021, 3022includes a hole or recess formed therein—member 3021 includes recess3015A and member 3022 includes recess 3015B. When the two members 3021,3022 are assembled with one another, the two holes 3015A and 3015B areplaced in alignment and form an elongated hole or recess 3015. Therecess 3015 is configured to receive a compression pin 3050 therein. Insome embodiments, the compression pin 3050 comprises a press pin that isforced into the elongated recess 3015. Advantageously, the compressionpin 3050 can comprise a butterfly or “FIG. 8” shape, whereby the pin3050 includes two larger, oversized ends surrounding a narrower centersection. By using such a pin 3050, the two or more bone members 3021,3022 can advantageously be joined together with at least a partiallycompressive force, with minimal purchase depth and in a manner thatprevents rotation of adjoining surfaces.

As shown in FIG. 62B, in some embodiments, the implant 10 can becomprised of two members 3021, 3022 that when adjoined have two holes3015—one of the upper face of the implant 10 and one on the lower faceof the implant 10. Each of the two holes 3015 can accommodate acompression pin 3050A, 3050B. With two separate compression pins, themulti-piece implant 10 can advantageously be secured on both the upperand lower surfaces.

As shown in FIGS. 62A and 62B, the implant 10 can also include one ormore recesses 3013 for engagement with an insertion instrument. As shownin the illustrated embodiment, each of the implants 10 includes anengagement recess 3013 on opposite sides. In some embodiments, theengagement recesses 3013 can advantageously be positioned adjacentbump-out portions 3014. The bump-out portions 3014 advantageously allowthe implant 10 to be secured to a plate, shown for example in FIG. 2A ofU.S. Ser. No. 13/785,434 filed on Mar. 5, 2013 and herein incorporatedby reference in its entirety, as the bump-out portions 3014 of theimplant 10 can be inserted and maintained in the windows (identified inthe '434 application by reference numeral 72) formed on the side arms ofthe plate.

FIG. 63 illustrates an unassembled implant with a FIG. 8 pin accordingto some embodiments. From this view, one can see that the implant 10 iscomprised of three different components—a first bone member 3021, asecond bone member 3022 and a compression pin 3050 in the form of a FIG.8. In some embodiments, the compression pin 3050 is a matching fit withthe recesses 3015A and 3015B, which adjoin to form an elongated recess3015. In other words, the shape and size of the compression pin 3050substantially or completely matches the shape and size of the elongatedrecess 3015. In other embodiments, the compression pin 3050 is of adifferent size and/or shape from the elongated recess 3015. For example,the compression pin 3050 can comprise two large rounded ends (as shownin FIG. 63), while the elongated recess 3015 can comprise edges (e.g.,such as part of a rectangle).

FIGS. 64A and 64B illustrate different views of an assembled implantwith a FIG. 8 pin according to some embodiments. From these views, onecan see the location of the elongated hole 3015 for receiving thecompression pin 3050 therein. As shown in the figures, the first bonemember 3021 and the second bone member 3022 can have ridges orprotrusions 3036 that extend on their superior and inferior surfaces,thereby helping to prevent expulsion of the assembled implant in betweentwo vertebral bodies. In some embodiments, and as shown in FIG. 64B, theelongate hole 3015 for receiving the compression pin 3050 can be formedon a side face of the implant 10, such that it is not cut into theprotrusions 3036 of the implant 10. While the embodiment herein shows asingle compression pin 3050, in other embodiments, two or morecompression pins 3050 can be provided to secure the implant 10. In someembodiments, the protrusions 3036, as well as an insertion chamfer onthe body of the implant, can be formed after assembling the two members3021, 3022 together with a compression pin 3050. In other embodiments,the protrusions 3036 and/or insertion chamfer are formed beforeassembling the two members 3021, 3022 together with a compression pin3050.

FIGS. 65A and 65B illustrate different views of a FIG. 8 pin accordingto some embodiments. As shown in the figures, the compression pin 3050is in the shape of a butterfly or FIG. 8 having a first large roundedsection 3056, a second large rounded section 3057 and a narrowermid-section 3060. The compression pin 3050 includes a superior surface3052 and an inferior surface 3054. While in the illustrated embodiment,the superior surface 3052 and the inferior surface 3054 do not havesurface ridges or protrusions, in other embodiments, the superiorsurface 3052 and inferior surface 3054 do have surface ridges orprotrusions. In addition, as shown in FIGS. 65A and 65B, the compressionpin 3050 can have a cut-out or chamfered portion 3070 that extendsaround the perimeter of the compression pin 3050. Such a cut-out orchamfered portion 3070 advantageously rounds the edges of thecompression pin 3050, thereby making the implant easier to insert into adisc space from any side of the implant. While the compression pin 3050is illustrated as having rounded edges in the illustrated embodiments,in other embodiments, the compression pin 3050 can have enlarged edgesor other shapes, including octagonal, square, or rectangular. In someembodiments, the compression pin 3050 can be in the shape of an i-beam.In addition, the compression pin 3050 need not be symmetrical. Forexample, enlarged section 3056 can be larger or shaped differently fromenlarged section 3057.

FIGS. 66A and 66B illustrate different views of an alternative FIG. 8pin according to some embodiments. The compression pin 3050 is of asimilar shape to the pin shown in FIGS. 65A and 65B and shares manysimilar features, including a first large rounded section 3056, a secondlarge rounded section 3057 and a narrower mid-section 3060. In contrastto the pin in FIGS. 65A and 65B, the pin 3050 comprises surface ridgesor protrusions 3059 that extend along superior and/or inferior surfacesof the pin 3050. Accordingly, the pin in FIGS. 66A and 66B can be usedon a superior surface and/or inferior surface of an implant that hasprotrusions, while the pin in FIGS. 65A and 65B can be used on a sidesurface in between superior and inferior surfaces of an implant, ifdesired.

FIGS. 67A-67G illustrate different views of a four-pin multi-pieceimplant according to some embodiments. The multi-piece implant 3110comprises an upper layer 3112 fixed to a lower layer 3114. In someembodiments, the upper layer 3112 and the lower layer 3114 are comprisedof bone (e.g., allograft bone). When the upper layer 3112 is alignedwith the lower layer 3114, a central hole 3119 is formed therein. Thecentral hole 3119 is advantageously provided to receive graft materialtherein. The upper layer 3112 and the lower layer 3114 each haveprotrusions, teeth, ribbing or ridges 3136 to assist in grippingadjacent vertebrae. While the implant 3110 is illustrated as having twolayers stacked vertically, in some embodiments, the four-pin implant3110 can comprise two layers stacked serially or side-by-side.

The upper layer 3112 is attached to the lower layer 3114 via fastenersor bone pins that extend through bore holes. In the present embodiment,four bone pins 3111 a, 3111 b, 3113 a, 3113 b are received through fourrespective bore holes 3186 a, 3186 b, 3188 a, 3188 b. As shown in FIG.67A, which shows a top view of the implant 3110, two pins 3111 a, 3111 bare inserted and extend through an upper surface of the implant 3110. Asshown in FIG. 67D, which shows a bottom view of the implant 3110, twopins 3113 a, 3113 b are inserted and extend through a lower surface ofthe implant 3110. It has advantageously been found that this four pinconfiguration, in which a pair is inserted through the upper surface anda pair is inserted through the bottom surface, provides the implant 3110with increased strength in assembly. In some embodiments, the pins arereceived in “blind” bore holes, whereby the bore holes are open at oneend but closed at an opposite end. As shown in FIGS. 67A and 67E, whichshow cross-sectional views of the implant 3110, the bore holes 3186 a,3186 b, 3188 a, 3188 b are each blind bore holes that do not extendcompletely though from an upper surface of the implant through a bottomsurface of the implant. By providing blind bore holes, thisadvantageously reduces the risk of the pins falling out of the implant.In some embodiments, one or more of the pins 3111 a, 3111 b, 3113 a,3113 b are at an angle relative to an interface between the two members3112, 3114.

In some embodiments, the implant 3110 can have a lordotic profile. Asshown in FIG. 67E, in some embodiments, the implant 3110 can have anupper surface that is at an angle to the midplane, and a lower surfacethat is at an angle to the midplane. By providing such features, theimplant 3110 is better able to accommodate the human anatomy in someinstances. In some embodiments, the implant 3110 can have an uppersurface and a lower surface that are parallel to one another.

To insert the implant 3110 into a patient, an insertion tool can be usedto grip surfaces of the implant 3110. To accommodate the insertion tool,the implant 3110 comprises a pair of side slots 3160 (shown best inFIGS. 67E and 67G). In other embodiments, the implant 3110 can includegripping surfaces formed on an upper surface and a lower surface of theimplant 3110.

FIGS. 68A-68E illustrate different views of an alternative multi-pieceimplant according to some embodiments. The implant 3210 comprises aninner member 3220 attached to a first lateral member 3232 and a secondlateral member 3234. As shown in the top cross-sectional view shown inFIG. 68D, the inner member 3220 is attached to the first lateral member3232 via a pair of fasteners or pins (e.g., bone pins) 3211 a, 3213 a.In addition, the inner member 3220 is attached to the second lateralmember 3234 via a pair of fasteners or pins (e.g., bone pins) 3211 b,3213 b.

As shown in FIG. 68A, the inner member 3220 comprises an annular memberincluding a pair of parallel flat outer surfaces separated by a pair ofcurved surfaces. The inner member 3220 includes a central opening orhole 3219 that can receive graft material therein. The first lateralmember 3232 comprises an inner surface that conforms to a first outersurface of the inner member 3220. In some embodiments, the inner surfacecomprises a concave surface. Likewise, the second lateral member 3234comprises an inner surface that conforms to a second outer surface ofthe inner member 3220. In some embodiments, the inner surface comprisesa concave surface. As shown in FIG. 68A, each of the first lateralmember 3232 and second lateral member 3234 comprises a crescent shape.

When the inner member 3220 is assembled to the first lateral member 3232and the second lateral member 3234 (as shown in FIG. 68A), the implant3210 is capable of being inserted in to a disc space between a firstvertebral body and a second vertebral body. In some embodiments, theimplant 3210 comprises a tapered leading end 3223. The tapered leadingend 3223 comprises one or more tapered surfaces that advantageously forma distraction nose. As shown in FIG. 68, the one or more taperedsurfaces can be protrusion-free. In some embodiments, when the innermember 3220 is assembled to the first lateral member 3232 and the secondlateral member 3234, the implant includes a flat or planar anteriorsurface and a flat or planar posterior surface.

In some embodiments, the assembled implant 3210 comprises an uppersurface 3212 and a lower surface 3214. In some embodiments, the uppersurface 3212 of the assembled implant 3210 comprises a curved, convexsurface. In some embodiments, the lower surface 3214 of the assembledimplant 3210 comprises a curved, convex surface. As shown in FIG. 68,both the upper surface 3212 and the lower surface 3214 canadvantageously comprise convex surfaces to better conform to an anatomyof a particular patient. In other embodiments, one or both of the uppersurface 3212 and lower surface 3214 can be flat or planar.

FIG. 68C illustrates a side profile of the assembled implant 3210. FIG.68C shows a side view of the implant 3210. From this view, one can seehow the implant 3210 resembles a wedge shaped member. The implant 3210comprises one or more gripping surfaces or slots 3260 that areconfigured to receive an instrument therein. The one or more slots 3260are formed on the sidewalls of the implant 3210. In some embodiments,the implant 3210 comprises a pair of slots for being gripped by aninstrument. In some embodiments, the implant 3210 comprises one or moregripping surfaces that extend on an upper or lower surface of theimplant 3210.

FIG. 68D shows a top cross-sectional view of the implant 3210 includingfour fasteners or bone pins 3211 a, 3211 b, 3213 a, 3213 b in accordancewith some embodiments. The bone pins 3211 a, 3213 a extend between theinner member 3220 and the first lateral member 3232, while the bone pins3211 b, 3213 b extend between the inner member 3220 and the secondlateral member 3234. As shown in FIG. 68D, each of the bone pins 3211 a,3211 b, 3213 a, 3213 b extend through blind bore holes. The blind boreholes each open on one of the lateral members 3232, 3234, but do notextend all the way into the central hole 3219. By providing blind boreholes, this advantageously reduces the risk of the undesireddisplacement of the bone pins. FIG. 68F shows an alternative topcross-sectional view, whereby the four fasteners or bone pins 3211 a,3211 b, 3213 a, 3213 b are oriented in a different direction. As opposedto the embodiment in FIG. 68D wherein pins 3211 a and 3213 a areoriented towards each other, in FIG. 68F, the pins 3211 a, 3213 a areoriented away from one another. Likewise, as opposed to the embodimentin FIG. 68D wherein pins 3211 b and 3213 b are oriented towards eachother, in FIG. 68F, the pins 3211 b and 3213 b are oriented away fromone another. With the pins oriented away from one another, as in FIG.68F, the pins advantageously end closer to the midplane of the implant3210, thereby providing a more secure assembly.

FIG. 68E shows a close-up view of a bone pin 3213 a extending throughthe first lateral member 3232 and the inner member 3220. As shown in thefigure, the first lateral member 3232 includes an inner curved surfacethat conforms to an outer curved surface of the inner member 3220,thereby forming an interface between the two members. In someembodiments, the bone pin 3213 a extends across the interface at anangle other than 0 or 90 degrees.

FIGS. 69A-69C illustrate different views of an alternative multi-pieceimplant according to some embodiments. The implant 3310 comprises aninner member 3320, a first lateral member 3332 and a second lateralmember 3334. In the present embodiment, the inner member 3320 comprisesa strut that extends across the implant, thereby forming two separategraft openings or holes 3319 a, 3319 b. As shown in FIG. 69A, the innermember 3320 can comprise a shaft or bar having a height less than theadjacent lateral members 3332, 3334. In some embodiments, the innermember 3320 comprises a first end that is received in a chamber of thefirst lateral member 3332 and a second end that is received in a chamberof the second lateral member 3334.

FIG. 69B shows a side view of the implant 3310 according to someembodiments. From the side view, one can see how the implant 3310resembles a tapered wedge member having a slanted upper surface 3312 anda slanted lower surface 3314. Also, from the side view, one can see howthe implant 3310 includes one or more slots 3360 that can be gripped byan instrument.

FIGS. 70A-70D illustrate different views of an alternative multi-pieceimplant according to some embodiments. The implant 3410 comprises anannular member having an inner member 3420 a first lateral member 3432and a second lateral member 3434. In some embodiments, the differentmembers can be formed of bone. The inner member 3420 divides the annularmember such that it has a first opening 3419 a and a second opening 3419b for receiving graft material therein.

FIG. 70B shows a front view of the implant 3410. From this view, one cansee the implant 3410 is convex along an upper surface 3412 and convexalong a lower surface 3414. The biconvex nature of the implantadvantageously allows the implant to be inserted in particular anatomiesof certain patients.

FIG. 70C shows a side view of the implant 3410. From this view, one cansee how the implant 3410 can be formed not just of members that areplaced laterally or serially next to one another, but also on top of oneanother. In some embodiments, the implant 3410 has different membersstacked on top of one another—an upper member 3412, a lower member 3414,and an intermediate member 3416. Each of the members can be formed ofbone. As shown in the figure, the implant is assembled together viadiagonal pin members 3411 b, 3413 b.

FIG. 70D shows a top cross-sectional view of the implant 3410. From thisview, one can see how the implant 3410 is held together by at least fourpins 3411 a, 3411 b, 3413 a, 3413 b. In some embodiments, the pins areformed of bone. The pins are advantageously capable of maintaining theimplant in an assembled configuration to allow the implant to beinserted into a disc space. In some embodiments, the pins extend througha blind bore hole, thereby reducing the risk of inadvertent pin backout.

FIGS. 71A-71C illustrate different views of an alternative multi-pieceimplant according to some embodiments. The implant 3510 comprises fivemembers assembled together, including an inner member 3520, a firstlateral member 3532, a second lateral member 3534, an upper member 3523and a lower member 3525. The inner member 3520 comprises a strut thatseparates the implant into a first chamber or graft opening 3519 a and asecond chamber or graft opening 3519 b.

FIG. 71C illustrates how the different members are attached to oneanother via bone pins. The first lateral member 3532 is attached to theupper member 3523 via a first bone pin 3511 a. Likewise, the secondlateral member 3534 is attached to the upper member 3523 via a secondbone pin 3511 b. The first lateral member 3532 is attached to the lowermember 3525 via a third bone pin 3513 a. Likewise, the second lateralmember 3534 is attached to the lower member 3525 via a fourth bone pin3513 b. The upper member 3523 is then attached to the inner member 3520via a fifth bone pin 3515 a. Likewise, the lower member 3525 is attachedto the inner member 3520 via a sixth bone pin 3515 b. Each of the bonepins are at an angle other than 0 or 90 degrees relative to an interfacebetween two members. Advantageously, by providing a six-pin assembly,the implant is of a sturdy nature and capable of being inserted into adisc space without disassembling.

FIGS. 72A-72D illustrate different views of an alternative multi-pieceimplant according to some embodiments. The implant 3610 comprises aninner member 3620, an upper inner receiver 3622 a for receiving theinner member 3620, a lower inner receiver 3622 b for receiving the innermember 3630, a first lateral member 3632 and a second lateral member3634. The first lateral member 3632 is attached to the upper innerreceiver 3622 a via a first bone pin 3611 a, while the second lateralmember 3634 is attached to the upper inner receiver 3622 a via a secondbone pin 3611 b. The first lateral member 3632 is attached to the lowerinner receiver 3622 b via a third bone pin 3613 a, while the secondlateral member 3634 is attached to the lower inner receiver 3622 b via afourth bone pin 3613 b.

FIG. 72C shows a side view of the implant 3610. The implant 3610comprises a slanted upper surface 3612 and a slanted lower surface 3614.As shown in FIG. 72C, the implant 3610 comprises a wedge-shaped member.

As shown in FIG. 72D, the inner member 3620 comprises a strut having anarrow proximal end and a narrow distal end. The narrowed ends arecapable of being received in respective receivers 3622 a, 3622 b. Insome embodiments, the receivers 3622 a, 3622 b comprise cup ortulip-shaped members designed and configured to receive the narrowedends of the inner member 3620. In some embodiments, the receivers 3622a, 3622 b advantageously serve as a catch for the different ends of theinner member 3620.

FIGS. 73A-73D illustrate different views of an alternative multi-pieceimplant according to some embodiments. The implant 3710 comprises fivemembers assembled together via four or more bone pins. In particular,the implant 3710 comprises an inner member 3720, a first lateral member3711 a, a second lateral member 3711 b, an upper member 3722 a and alower member 3722 b. The inner member 3720 comprises a strut thatseparates the implant 3710 into two chambers or graft openings 3719 aand 3719 b. The implant comprises a pair of side slots 3760 for beinggripped by an insertion instrument or tool.

FIGS. 74A-74D illustrate different views of an alternative multi-pieceimplant according to some embodiments. The implant 3810 comprises threemembers assembled together into one unit—an inner member 3820, a firstlateral member 3832 and a second lateral member 3834. The members areheld together via fasteners or pins, as shown in the top cross-sectionalview illustrated in FIG. 74D.

As shown in FIG. 74A, the implant 3810 comprises an inner member 3820having a central graft opening 3819 formed therethrough. The innermember 3820 comprises an annular member having a generally round orcircular perimeter. In some embodiments, the central graft opening 3819formed therein is circular, while in other embodiments, the opening 3819can have one or more flat sides. The inner member 3820 is bounded oneach side by lateral members 3832, 3834. Each of the lateral members3832, 3834 comprises a curved inner surface that matches a portion ofthe perimeter of the inner member 3820.

When assembled, the inner member 3820 and lateral members 3832, 3834comprise a unit insertable into a disc space. As shown in FIG. 74C, theunit comprises an upper surface 3812 and a lower surface 3814. In someembodiments, the upper surface 3812 is parallel to the lower surface3814, while in other embodiments, the upper surface 3812 and lowersurface 3814 can be lordotic such that they are not parallel to oneanother.

As shown in FIG. 74D, the members of the implant 3810 are assembledtogether via one or more pins 3811 a, 3811 b, 3813 a, 3813 b. The pins3811 a, 3811 b, 3813 a, 3813 b are each positioned diagonally to aninterface formed between the inner member 3820 and the lateral members3832, 3834.

FIGS. 75A-75D illustrate different views of an alternative multi-pieceimplant according to some embodiments. The implant 3910 comprises aninner member 3920, a first lateral member 3932 and a second lateralmember 3934. The implant 3910 is similar to that shown in FIG. 68 inthat the members are attached to one another via four pin members 3911a, 3911 b, 3913 a, 3913 b (shown in FIG. 75D). In addition, the implant3910 comprises a tapered upper surface 3912 and a tapered lower surface3914 (shown in FIG. 75C) such that the implant 3910 resembles a wedgeshaped member. In contrast, however, in its assembled state, the implant3910 includes a non-planar anterior face and a non-planar posteriorface. In some embodiments, the anterior face and the posterior face arecurved to better accommodate a particular anatomy of a patient.

FIGS. 76A-76D illustrate different views of an alternative multi-pieceimplant according to some embodiments. The implant 4010 comprises aninner member 4020 that is attached to a pair of lateral members 4032,4034. The inner member 4020 surrounds a central opening 4019 which isdesigned to receive graft material therein. As shown in FIG. 76A, thelateral members 4032, 4034 each have a height that is less than anoverall height of the inner member 4020, such that the implant 4010acquires a distinct shape suitable to a particular anatomy of a patient.In some embodiments, the inner member 4020 is attached to the lateralmembers 4032, 4034 via pin members 4011 a, 4011 b, 4013 a, 4013 b asshown in FIG. 76D.

FIGS. 77A-77E illustrate different views of an alternative multi-pieceimplant according to some embodiments. The implant 4110 comprises anannular member 4120 positioned adjacent to a partial annular member4132. The partial annular member 4132 is capable of sliding over asurface 4126 (shown in FIG. 77B) of the annular member 4120, therebyforming an assembled unit.

FIG. 77C shows an anterior view of the implant 4110. From this view, onecan see how the implant has a curved upper surface 4112 and a curvedlower surface 4114. In addition, the implant 4110 comprises a pair ofslots 4140 formed on upper and lower surfaces of the implant. The slots4140 advantageously allow for gripping by an instrument or tool forimplant insertion.

FIG. 77E shows a top cross-sectional view of the implant 4110. As shown,the annular member 4120 is attached to the partial annular member 4132via a pair of pins 4111, 4113. The pins 4111, 4113 are advantageouslyreceived in blind bore holes and maintain the implant 4110 in a strongassembly.

FIGS. 78A-78C illustrate different views of an alternative multi-pieceimplant according to some embodiments. The implant 4210 comprises afirst annular member 4220 and a second annular member 4222 held togetherby pin members 4211, 4213. As shown in FIG. 78B, the first annularmember 4220 comprises a pair of recesses 4228, 4229 for receiving thesecond annular member 4222 therein. With the second annular member 4222received in the first annular member 4220, a pair of pin members 4211,4213 can be downwardly inserted through the implant, thereby holding theimplants in place. By providing a pair of annular members, the implant4210 advantageously provides multiple inner chambers for receiving graftmaterial therein.

Additional Characteristics

In addition to those features discussed above, additional features arenow described. Any combination of features are possible to include inthe implants discussed above.

In some embodiments, the implants can be formed of allograft, xenograft,synthetic material or combinations thereof. Specific materials possiblefor use include cortical bone, cancellous bone, cortico-cancellous bone,collagen, PEEK, titanium, stainless steel, PLA, PLDL and othermaterials.

In some embodiments, the implants are formed monolithically. In otherembodiments, the implants are multi-piece, and are composed of two ormore layers. The layers can be generally planar; however, in someembodiments, the multi-piece implant can include non-planar components.For example, an implant can comprise a first portion comprised of asquare block member with a square hole formed therein and a secondportion that is capable of filling in the hole.

The implants can be incorporated in multiple levels of the spine. Forexample, the implants described above can be suited for use in thecervical, thoracic and lumbar regions of the spine.

In some embodiments, the implants have substantially planar superior andinferior surfaces that are parallel and are not lordotic. In someembodiments, these implants can have anterior and posterior sides ofsimilar height. In other embodiments, the implants have a degree oflordosis, such as up to 20 degrees with respect to a midplane. In someembodiments, these lordotic implants can have curved edges and/or curvedupper/lower sides.

The implants described above can include a mid-plane that extends alength between a superior surface and an inferior surface. In someembodiments, the superior surface and inferior surface are parallel tothe mid-plane. In other embodiments, only one of the superior surfaceand inferior surface are parallel to the mid-plane. And in anotherembodiment, neither the superior surface nor the inferior surface areparallel to the mid-plane.

The implants discussed above can have anterior, posterior and sidewallsof various shapes. For example, the walls can be curved, planar andangled.

For multi-layered implants composed of two or more layers, variousinterfaces can be formed between the implants. For example, the implantcan include a mating face interface that is flat, curved, slanted,waffle-patterned, dovetail-patterned, t-shaped, lego, textured, or anyother shape.

In some embodiments, the superior and/or inferior faces can includeroughened surfaces. The roughened surfaces can include teeth, ribs,ridges, or any other types of surface protrusion. Among the surfacesthat can include three-sided teeth, four-sided teeth, five-sided teeth,six-sided teeth and more, ridges, conical protrusions, saw teeth,pyramidal teeth and simple textures. In some embodiments, the tip of thesurface protrusions can be rounded, sharp, flat, blunt or concave.

The implants can include a number of different insertion features. Amongthe insertion features include parallel slots, converging slots,dimples, channels, nubs, holes (threaded) and holes (non-threaded).These insertion features can be located in one or more places of theimplant body, including into the body of the implant, along side walls,or on superior and inferior surfaces.

In some embodiments, the implants can include one or more graft holes.The graft holes can be of various shapes, including circular,triangular, square, oval tear-drop, tapered, trapezoidal andrectangular. In some embodiments, the graft holes have a length that isgreater than the width of adjacent walls, while in other embodiments,the graft holes have a length that is less than the width of adjacentwalls. The graft holes can be placed in a number of positions, such ascentrally, offset in an anterior-posterior direction, offset in amedial-lateral direction, or offset diagonally. In some embodiments, thegraft hole can be formed of two or more holes that are aligned, while inother embodiments, the graft hole can be formed of two or more holesthat overlap but may be axially offset from one another.

While the invention herein disclosed has been described by means ofspecific embodiments and applications thereof, numerous modificationsand variations can be made thereto by those skilled in the art withoutdeparting from the scope of the invention.

What is claimed is:
 1. An intervertebral implant comprising: an innermember having an upper contact surface, a lower contact surface, a firstouter wall, and a second outer wall; a first lateral member, wherein thefirst lateral member comprises a surface that conforms to the firstouter wall of the inner member at a first interface; a second lateralmember, wherein the second lateral member comprises a surface thatconforms to the second outer wall of the inner member at a secondinterface; a first pin, formed separately from the inner member,extending through the first interface; and a second pin, formedseparately from the inner member, extending through the secondinterface, wherein one of the first and second pins is positioneddiagonally to the first or second interface, respectively.
 2. Theimplant of claim 1, wherein the first and second outer walls each have acurved surface that extends from the upper contact surface to the lowercontact surface.
 3. The implant of claim 1, wherein the inner member,the first lateral member and the second lateral member are each formedof bone.
 4. The implant of claim 1, wherein when the inner member, thefirst lateral member and the second lateral member are assembled, theimplant includes a planar anterior surface.
 5. The implant of claim 4,wherein when the inner member, the first lateral member and the secondlateral member are assembled, the implant further includes a planarposterior surface.
 6. The implant of claim 1, further comprising a thirdpin extending through the inner member and the first lateral member, anda fourth pin extending through the inner member and the second lateralmember.
 7. The implant of claim 1, wherein when the inner member, thefirst lateral member and the second lateral member are assembled, theimplant includes a convex upper surface.
 8. The implant of claim 7,wherein when the inner member, the first lateral member and the secondlateral member are assembled, the implant includes a convex lowersurface.
 9. The implant of claim 1, wherein the first pin extendsthrough a blind bore hole.
 10. The implant of claim 9, wherein the blindbore hole begins on an outer surface of the first lateral member andextends through the first lateral member and into the inner member. 11.The implant of claim 1, wherein when the inner member, the first lateralmember and the second lateral member are assembled, the implantcomprises a contiguous upper contact surface, a contiguous lower contactsurface, a planar anterior surface, a planar posterior surface, a firstcurved sidewall and a second curved sidewall.
 12. An intervertebralimplant comprising: an inner member having an upper contact surface, alower contact surface, a first outer wall, and a second outer wall; afirst lateral member, wherein the first lateral member comprises asurface that conforms to the first outer wall of the inner member at afirst interface; a second lateral member, wherein the second lateralmember comprises a surface that conforms to the second outer wall of theinner member at a second interface; and a first pin, formed separatelyfrom the inner member, extending through the first interface; and asecond pin, formed separately from the inner member, extending throughthe second interface, wherein the first pin is positioned diagonally tothe first interface and the second pin is positioned diagonally to thesecond interface.
 13. The implant of claim 12, wherein the inner member,the first lateral member and the second lateral member are formed ofbone.
 14. The implant of claim 12, wherein the first pin and the secondpin are formed of bone.
 15. The implant of claim 12, wherein the firstlateral member comprises a concave surface that conforms to the firstouter wall of the inner member.
 16. The implant of claim 15, wherein thefirst pin extends through the first lateral member and the inner membervia a blind bore hole.
 17. The implant of claim 12, wherein when theinner member, the first lateral member and the second lateral member areassembled, the implant comprises a planar anterior surface and a planarposterior surface.
 18. The implant of claim 17, wherein when the innermember, the first lateral member and the second lateral member areassembled, the implant comprises a first curved sidewall and a secondcurved sidewall that separates the planar anterior surface from theplanar posterior surface.
 19. The implant of claim 12, wherein the innermember defines a central opening, and the central opening is circular.20. The implant of claim 12, wherein when the inner member, the firstlateral member and the second lateral member are assembled, an uppersurface of the implant is convex.